Wednesday, January 31, 2007

In September 2005, hundreds of deep crevices appeared within a few weeks, and parts of the ground shifted eight metres overnight. More than two billion cubic metres of rising magma had seeped into a crack between the African and Arabian tectonic plates, forcing them further apart.

"Much of the activity between the continental shelves takes place deep underwater at the mid-ocean ridges. Ethiopia is the only place on the planet where we can see a continent splitting apart on dry land."

Dr. Wright and his colleagues will use satellite radar imaging to measure how the ground deforms. "In its simplest form, you are taking two snapshots of the same place, separated by a period of time, to see how far they have moved apart."

As the sides of the Ethiopian rift move apart, the gap between them is being plugged with molten rock, which then cools to form new land. And in around one million year's time the Red Sea could come flooding into the sinking region, re-shaping the map of Africa forever.

"It's very exciting because we're witnessing the birth of a new ocean," said Dr Wright. "In geological terms, a million years is the blink of an eye. We don't precisely know what is going to happen, but we believe that it may turn parts of Northern Ethiopia and Eritrea into an island, before a much larger land mass, the horn of Africa, breaks off from the continent."

Darwin here supports his views via analysis of various aspects of plant and animal life, including an inventory of varieties and their physical and behavioral characteristics, and an investigation of the impact of a species' surrounding environment and the effect of both natural and forced changes in this environment. link

Not so, said Dean Falk who created detailed maps of imprints left on the ancient hominid's braincase and concluded that the so-called Hobbit was actually a new species closely related to Homo sapiens.

A computer image depicts the brains (red) of a modern human with microcephaly (left), and the fossil specimen of Homo floresiensis (right).Image courtesy of Kirk E. Smith, ERL, Mallinckrodt Institute of Radiology

Now after further study, Falk is absolutely convinced that her team was right and that the species cataloged as LB1, Homo floresiensis, is definitely not a human born with microcephalia — a somewhat rare pathological condition that still occurs today. Usually the result of a double-recessive gene, the condition is characterized by a small head and accompanied by some mental retardation.

The debate stemmed from the fact that archaeologists had found sophisticated tools and evidence of a fire near the remains of the 3-foot-tall adult female with a brain roughly one-third the size of a contemporary human.

"People refused to believe that someone with that small of a brain could make the tools. How could it be a sophisticated new species?"

It's tomorrow!

But that's exactly what it is, according to Falk, whose team had previously created a "virtual endocast" from a three-dimensional computer model of the Hobbit's braincase, which reproduces the surface of the brain including its shape, grooves, vessels and sinuses. The endocasts revealed large parts of the frontal lobe and other anatomical features consistent with higher cognitive processes.

"LB1 has a highly evolved brain," she said. "It didn't get bigger, it got rewired and reorganized, and that's very interesting."

The paper should be up at the PNAS Early Edition as of jan. 29, but I’ve not seen it there yet.

The American Museum of Natural History has created America's first doctoral program at a museum.

Dr. John Flynn, a lead curator at the museum for the past two years, was chosen as dean of the Richard Gilder Graduate School at the museum. Flynn currently holds faculty positions at Columbia University and City University of New York. He also served for a decade as the associate chairman of the evolutionary biology doctoral program at the University of Chicago.

The Gilder school, which has raised about $50 million from three private donors and the city, will begin its comparative biology doctoral program next year.

Sunday, January 28, 2007

Eugene Dubois (Jan. 28, 1858 - Dec. 16, 1940) joined the Dutch Army as a medical officer, and used spare time from his medical duties to search for fossils, first in Sumatra and then in Java. He searched on the banks of the Solo River, with two assigned engineers and a crew of convict labourers to help him. In September 1890, his workers found a human, or human-like, fossil at Koedoeng Broeboes. This consisted of the right side of the chin of a lower jaw and three attached teeth. In August 1891 he found a primate molar tooth.

Two months later and one meter away was found an intact skullcap, the fossil which would be known as Java Man. In August 1892, a third primate fossil, an almost complete left thigh bone, was found between 10 and 15 meters away from the skullcap.

In 1894 Dubois published a description of his fossils, naming them Pithecanthropus erectus (now Home erectus), describing it as neither ape nor human, but something intermediate. In 1895 he returned to Europe to promote the fossil and his interpretation. A few scientists enthusiastically endorsed Dubois' work, but most disagreed with his interpretation. Many scientists pointed out similarities between the Java Man skullcap and Neandertal fossils.

Around 1900 Dubois ceased to discuss Java Man, and hid the fossils in his home while he moved on to other research topics. geology and paleontology. It was not until 1923 that Dubois, under pressure from scientists, once again allowed access to the Java Man fossils. That and the discovery of similar fossils caused it to once again become a topic of debate.

A recent fossil discovery in South China, combined with fossils found in 1998 and 2000 could reveal how the earliest known egg-laying organism developed from embryo to adulthood.

Researchers discovered thousands of 600-million-year-old fossilized embryos in the Doushantuo Formation nine years ago. Two years later, the same team unearthed fossils of a tubular coral-like animal, named Megasphaera ornata, which appeared to be adult versions of the embryos discovered earlier.

The case for a relationship between the two fossil types grew stronger following the recent discovery of about 80 intermediate-stage fossils that have traits in common with both groups.

On the outside, the early and intermediate stage embryos look very similar. They are about the same size -- about 0.02 inches wide or about as big as a grain of sand -- and both have similar outer coverings, or embryonic envelopes.

Using microCT scans found 3D structures that look like grooves on a screw.Traces of these coils are also found on the external coverings of the adult fossils. Some of the intermediate embryos also appeared to be unfurling, encouraging the speculation that if the process had continued, the embryos would distend like a stretched slinky or a flattened fuselli noodle into the tubular adult form.

Listen to or download the Jan. 27, 2007, interview with Dr. Shuhai Xiao on CBC’s “Quirks & Quarks”HERE. (Scoll down to find the link)

I recently came across this new image by our old friend Bill Stout. It’s always good to see more of Bill’s dinos but I’m not really sure what this is all about (although I suspect that the title says it all…)

Note: After resisting as long as possible, the Palaeoblog has been forced to switch to the “new, improved” version of blogger by blogger.com and the über-lord google.com. Although the look of the blog will not change significantly it does mean that the custom formatting of images that we’ve been able to do in the past is now almost impossible.

That’s me in front with the white shirt and blue hat, Nam-Soo Kim to my right (blue shirt), Young-Nam Lee to his right, Phil Currie to my left (khaki pants), Yoshi Kobayashi in the middle with the bandana, Junchang Lu with the sailing hat (middle left), Kyo-Young Song, and the rest of our Mongolian crew. Eva Koppelhus shot the clip on my pocket Nikon camera.

Sometime soon all of these promised video clips (in crystal clear format) will be up on a stand-alone KID web page. Enjoy!

Adventurer, administrator, and Museum promoter — Andrews spent his entire career at the American Museum of Natural History, where he rose through the ranks from departmental assistant, to expedition organizer, to Museum director. He became world famous as leader of the Central Asiatic Expeditions, a series of expeditions to Mongolia that collected, among other things, dinosaur eggs. But on these expeditions, Andrews himself found few fossils, and during his career he was not known as an influential scientist. Instead, Andrews filled the role of promoter, creating immense excitement and successfully advancing the research and exhibition goals of the museum.

Abstract:Microraptor gui, a four-winged dromaeosaur from the Early Cretaceous of China, provides strong evidence for an arboreal-gliding origin of avian flight.

It possessed asymmetric flight feathers not only on the manus but also on the pes. A previously published reconstruction shows that the hindwing of Microraptor supported by a laterally extended leg would have formed a second pair of wings in tetrapteryx fashion.

However, this wing design conflicts with known theropod limb joints that entail a parasagittal posture of the hindlimb. Here, we offer an alternative planform of the hindwing of Microraptor that is concordant with its feather orientation for producing lift and normal theropod hindlimb posture.

In this reconstruction, the wings of Microraptor could have resembled a staggered biplane configuration during flight, where the forewing formed the dorsal wing and the metatarsal wing formed the ventral one. The contour feathers on the tibia were positioned posteriorly, oriented in a vertical plane for streamlining that would reduce the drag considerably.

Leg feathers are present in many fossil dromaeosaurs, early birds, and living raptors, and they play an important role in flight during catching and carrying prey. A computer simulation of the flight performance of Microraptor suggests that its biplane wings were adapted for undulatory "phugoid" gliding between trees, where the horizontal feathered tail offered additional lift and stability and controlled pitch.

Like the Wright 1903 Flyer, Microraptor, a gliding relative of early birds, took to the air with two sets of wings.

Thursday, January 25, 2007

Dobzhansky is noted for being one of the architects of the modern Synthetic Theory of evolution. During the first 20 years of the 20th century, Darwin's theory of natural selection had fallen out of favor among scientists. Many thought it insufficient to explain the origin of adaptations, while new discoveries of gene mutations seemed to them to be incompatible with Darwinian models of change.

But in 1937Dobzhanskypublished his book, Genetics and the Origin of Species, that was the first systematic overview view encompassing organic diversity, variation in natural populations, selection, isolating mechanisms (a term he coined) and species as natural units.

Later, working with Sewall Wright, he went on to demonstrate how evolution can produce stability and equilibrium in populations rather than constant directional change. link. image.

First discovered in 2002, the three- to four-million-year-old Nullarbor Plain caverns have yielded fossils of 70 animal species dating from 800,000 to 400,000 years ago, including 10 intact skeletons of Thylacoleo, nearly hippo-size giant wombat, and 23 kangaroo species—8 of them new to science.

The rich diversity of species found in the ancient caves shows that life was similarly thriving in the region during the Ice Age. Two new species of tree kangaroos, for example, indicate that 300,000 years ago Nullarbor Plain wasn't as treeless as its name implies.

According to John Long, the findings "have virtually nailed that climate change wasn't a major factor" in the animals' extinction.

The scientists therefore believe that hunting pressures and wildfires linked to ancient humans may have finally tipped the balance against Australia's large animals.

A strikingly unusual large rodent related to spiny rats was recently discovered in the cloud-forests of Peru.

Isothrix barbarabrownae by Nancy Halliday, The Field Museum

The nocturnal, climbing Isothrix barbarabrownae is beautiful yet strange looking, with long dense fur, a broad blocky head, and thickly furred tail. A blackish crest of fur on the crown, nape and shoulders add to its distinctive appearance.

I. barbarabrownae belongs to a family of rodents known as "spiny rats" because most of the species in that family bristle with spines. Its discovery has necessitated a re-examination of this tropical American family, especially its closest relatives, the bush-tailed tree rats found in South America's lowlands.

The authors of the study found the rodent in 1999 while conducting field research in Peru's Manu National Park and Biosphere Reserve Mountains in Southern Peru along the eastern slope of the Andes. Extending from lowland tropical forests in the Amazon Basin to open grasslands above the Andean tree line, Manu is home to more species of mammals and birds than any equivalently sized area in the world.

The new rodent was discovered at an altitude of 6,200 feet. Little is known about its lifestyle because subsequent efforts to locate and observe the animal were fruitless.

"The new species is not only a handsome novelty," Patterson said. "Preliminary DNA analyses suggest that its nearest relatives, all restricted to the lowlands, may have arisen from Andean ancestors. The newly discovered species casts a striking new light on the evolution of an entire group of arboreal rodents."

Researchers describe two new 56-million-year-old fossils, including the most primitive primate skeleton ever described. The new plesiadapiform species, Ignacius clarkforkensis and Dryomomys szalayi, were found just outside Yellowstone National Park in the Bighorn Basin.

An extensive evaluation of skeletal structures provides evidence that plesiadapiforms, a group of archaic mammals once thought to be more closely related to flying lemurs, are the most primitive primates.

At least five major features characterize modern primates: relatively large brains, enhanced vision and eyes that face forward, a specialized ability to leap, nails instead of claws on at least the first toes, and specialized grasping hands and feet. Plesiadapiforms have some but not all of these traits. The article argues that these early primates may have acquired the traits over 10 million years in incremental changes to exploit their environment.

Scientists have shown that Titanis walleri, a prehistoric 7-foot-tall flightless “terror bird,” arrived in North America from South America long before a land bridge connected the two continents using analysis of rare earth elements.

“It was previously thought that Titanis immigrated to Texas across the Panamanian land bridge that formed about 3 million years ago connecting North and South America,” said MacFadden. “But the rare earth element analysis of a fossil Titanis bone from Texas determines its age to be 5 million years old. This shows that the bird arrived 2 million years before the land bridge formed, probably across islands that formed what today is the Isthmus of Panama.”

The terror bird was carnivorous, weighed about 330 pounds, had powerful feet and a head larger than a man’s. It is known in the fossil record from a single toe bone in Texas, and in Florida by about 40 bone fragments from different skeletal regions. MacFadden’s team also analyzed six specimens from the Santa Fe River in north Central Florida.

“We found that the Titanis fossils were 2 million years old and not 10,000 years old as had been suggested,” MacFadden said. “This also shows the last known occurrence of Titanis in the fossil record and reflects its extinction.”

Geologists have used the technique to study igneous and metamorphic rocks, but only one other researcher worldwide has applied this technique to date the age of fossils: professor Clive Trueman from the University of Southampton in England.

“It is very difficult to assess the age of fossil bones directly as they are too old to be carbon dated,” Trueman wrote in an e-mail. “Bones can also be moved after death, further confusing their true age. MacFadden’s approach compares bones of disputed age with those of known age. If the chemistry matches, the bones are of the same age irrespective of their final resting place.”

The study will be published Jan. 23 in the online version of the journal Geology and featured in its February print edition. I’ll add the link once it is posted.

Saturday, January 20, 2007

Ok, this is really peripheral to ‘palaeo’ but I know that some of you will enjoy it--a stabilized version of the infamous Patterson-Gimlin "Bigfoot" film, steadied so you can see how the person dressed in the creature suit really walks.

Abstract: In South America, most titanosaur species are represented by incomplete skeletal elements lacking well-preserved cervical vertebrae. In this context, the discovery of cervical remains assigned to Mendozasaurus neguyelap González Riga is relevant from a systematic viewpoint. The fossils were found in the paleontological site and assemblage of the holotype, Río Neuquén Subgroup, late Turonian – late Coniacian from Mendoza Province, Argentina.

The cervical vertebrae of Mendozasaurus exhibit differences with those of most titanosaurs; however, they share with Isisaurus colberti (Jain and Bandyopadhyay) from Maastrichthian of India the presence of: a) short vertebral centra (ratio: total length/height of cotyle less than 2.5), b) large and deep supradiapophyseal fossa, and c) relatively tall neural spines (ratio: vertebral height/centrum length more than 1.5).

The fossils recovered show an autapomorphic character that enlarges the diagnosis of Mendozasaurus: tall, laminar and transversally expanded mid-posterior cervical neural spines that are wider than vertebral centra and ‘fan-like' or ‘subrhomboid' in shape due to lateral expansions and a subrounded dorsal border.

The fossil record of titanosaurs shows a notable morphologic diversity in the cervical series. In particular, Mendozasaurus neguyelap and Isisaurus colberti possess tall neural spines associated with the proportionally shortest cervical centra of any titanosaur. This unusual morphology suggests the development of relatively wide, robust and short necks in Late Cretaceous sauropods from Argentina and India.

Thanks to Dr. Eric Snively for pointing out this older but still interesting paper to the Palaeoblog!

My buddy, Dr. Steve Cumbaa from the Canadian Museum of Nature, will lead a workshop about fossils on Thursday, January 25 from 7:00 p.m to 9:30 p.m. at the CMN at 240 McLeod Street in Ottawa, Ontario. The workshop will include a slide show of palaeontological field work and then hands-on work examining and sorting marine and coastal fossils from North America.

The fee is only $10 and the workshop is free for participants who have an individual membership to the Museum of Nature. Space is limited and registration is required by calling 613-566-4791.

Thursday, January 18, 2007

DNA preserved in bones undergoing fossilization deteriorates up to 50 times faster when stored in a museum than when the bones are buried in the ground.

This study shows that in order to improve the quality of paleogenetic analyses, archeological and paleontological remains should be treated like biological samples both during and after excavation.

An extensive study of around 250 fossil bones from 600 to 50 000 year old herbivores showed that mitochondrial DNA from freshly excavated, untreated fossil bones was amplified with a success rate of 46%. However, the rate is a mere 18% for fossil bones from collections which have been washed, dried and stored.

These findings were confirmed by a study on fossil bones from a single animal, an aurochs which became buried 3 200 years ago in the Sarthe region of France. The fossil bones were excavated during two excavation campaigns, the first carried out in 1947, and the second in 2004. None of the fossil bones excavated in 1947 and stored in the Musée Vert yielded any results from paleogenetic analysis. On the other hand, DNA amplification was obtained with all the 2004 fossil bones, thus yielding significant results from paleogenetic analysis.

Another finding revealed by this study was that the DNA had deteriorated as much in 57 years as during the previous two thousand years of burial. link

Tuesday, January 16, 2007

Researchers examine the relationship of predator mass and energy expenditure in capturing prey of varying sizes and reveal how this relationship might have led to the extinction of large carnivores in the past.

By analyzing the balance between energy intake and expenditure across a range of species, the authors reveal that mammalian carnivores would not be able to exceed a body mass of one ton. Their model predictions are consistent with the data we have. Most mammalian carnivores are relatively small compared with the largest extinct terrestrial herbivorous mammals, such as the Indricothere (above), which weighed around 15 tons.

The largest existing carnivore, the polar bear, is only around half a ton, while the largest known extinct carnivores, such as the short-faced bear, weighed around one ton.

The authors also note that the largest terrestrial non-mammalian predators, such as Giganotosaurus and Tyrannosaurus, may have achieved their massive size by having a lower metabolic rate. Indeed, previous estimates of total metabolic rate for these species are similar to those of a mammal weighing about a ton.

Carnivores at the upper limits of body mass would have been heavily reliant on abundant large prey to both minimize energy expenditure and maintain high rates of energy intake. Slight environmental perturbations, man-made or otherwise, leading to lower prey availability, could readily upset this energy balance. It may have also contributed to the extinction of the largest carnivores and explain why the largest modern mammalian carnivores are so rare and vulnerable today.

Monday, January 15, 2007

SHOWCASE PRESENTS: THE WAR THAT TIME FORGOT VOL. 1 TPWritten by Robert Kanigher, Art by Ross Andru & Mike Esposito

Over 500 pages of classic adventures are included in this value-priced volume collecting one of the most unusual series ever from DC Comics! On an unnamed, uncharted Pacific island, dinosaurs continued to thrive while World War II raged across the globe. It’s there that members of the U.S. Military found themselves armed only with standard-issue weapons against the deadliest predators ever to roam the Earth! On sale May 2 • 560 pg, B&W, $16.99 US

On this day in 1759, the British Museum, in Bloomsbury, London, the world's oldest public national museum, opened to the public who were admitted in small groups, by ticket obtained in advance, for a conducted tour.

It was established on June 7, 1753 when King George II gave his royal assent to an Act of Parliament to acquire the collection of Sir Hans Sloane. In his will, he had offered the nation his lifetime collection of 71,000 objects, mostly plant and animal specimens. In return, he requested £20,000 for his heirs (which today would be over £2,000,000). The present museum buildings date from the mid-19th century. Its natural history collection moved to its own museum in 1881.link

Sunday, January 14, 2007

Above are the first three strips featuring Alley Oop and his beloved dinosaur, Dinny, just after their first encounter where they become fast friends. These strips from V.T. Hamlin’s classic cartoon were scanned from the reprint collection, “Alley Oop” #1 (1987), from Dragon Lady Press .

Huge carnivorous reptiles and giant flesh-eating fish have taken up residence at the Berkshire Museum in the new exhibit, "Savage Ancient Seas." The extinct creatures, in fossil, skeleton and replica form, are from the late Cretaceous period, more than 70 million years ago.

"Savage Ancient Seas" was organized by Triebold Paleontology Inc. in Woodland Park, Colo. The exhibit was previously at the CMNH and I highly recommend viewing the exhibit if you’re in the area.

Adolphe-Théodore Brongniart was a French botanist whose classification of fossil plants drew surprisingly accurate relations between extinct and existing forms prior to Charles Darwin's principles of organic evolution. His work earned him the distinction as the founder of modern paleobotany.

He was an early proponent of evolutionary theory. Brongniart published the first complete account of fossil plants (1828). His interpretations of the fossil record also contributed to our understanding of historical changes in climates and plant geography. linkimage

The evidence consists of stone, bone and ivory tools discovered under a layer of ancient volcanic ash on the Don River in Russia some 250 miles south of Moscow. Thought to contain the earliest evidence of modern humans in Europe, the site also has yielded perforated shell ornaments and a carved piece of mammoth ivory that appears to be the head of a small human figurine, which may represent the earliest piece of figurative art in the world, he said.

"The big surprise here is the very early presence of modern humans in one of the coldest, driest places in Europe," Hoffecker said. "It is one of the last places we would have expected people from Africa to occupy first."

While there is some evidence Neanderthals once occupied the plains of Eastern Europe, they seem to have been scarce or absent there during the last glacial period when modern humans arrived, he said. The lack of competitors like the Neanderthals might have been the chief attraction to the area and the reason why modern humans first entered this part of Europe, Hoffecker said.

A human skull discovered over fifty years ago near the town of Hofmeyr, in the Eastern Cape Province of South Africa has been dated the skull to 36,000 years ago. This skull provides critical corroboration of genetic evidence indicating that modern humans originated in sub-Saharan Africa and migrated about this time to colonize the Old World.

Wednesday, January 10, 2007

Abstract: The immensely long neck of a sauropod is one of the most familiar and striking of anatomical specializations among dinosaurs. Here, I use recently collected neontological and paleontological information to test the predictions of two competing hypotheses proposed to explain the significance of the long neck.

According to the traditional hypothesis, neck elongation in sauropods increased feeding height, thereby reducing competition with contemporaries for food. According to the other hypothesis, which is advanced for the first time here, neck elongation in sauropods was driven by sexual selection. Available data match the predictions of the sexual selection hypothesis and contradict the predictions of the feeding competition hypothesis. It is therefore more plausible that increases in sauropod neck lengths were driven by sexual selection than by competition for foliage.

Steno (a.k.a. Niels Steensen, or Stensen) was a Danish geologist and anatomist who first made unprecedented discoveries in anatomy, then established some of the most important principles of modern geology. He was Danish royal anatomist for 2 years.

Interested by the characteristics and origins of minerals, rocks, and fossils, he published in Prodromus (1669) the law of superposition (if a series of sedimentary rocks has not been overturned, upper layers are younger and lower layers are older) and the law of original horizontality (although strata may be found dipping steeply, they were initially deposited nearly horizontal.) linkimage